To avoid kernel memory leakage into user space, memory should be manually
allocated instead of using memory from the kernel stack.
Reported-and-tested-by: syzbot+cfc08744435c4cf94a40@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
kernel/ptrace.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index d8b5e13a2229..8bd346b10c6e 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -1033,7 +1033,7 @@ int ptrace_request(struct task_struct *child, long request,
{
bool seized = child->ptrace & PT_SEIZED;
int ret = -EIO;
- kernel_siginfo_t siginfo, *si;
+ kernel_siginfo_t siginfo, *si, *psiginfo;
void __user *datavp = (void __user *) data;
unsigned long __user *datalp = datavp;
unsigned long flags;
@@ -1061,9 +1061,13 @@ int ptrace_request(struct task_struct *child, long request,
break;
case PTRACE_GETSIGINFO:
- ret = ptrace_getsiginfo(child, &siginfo);
+ psiginfo = kvmalloc(sizeof(kernel_siginfo_t), GFP_KERNEL);
+ if (!psiginfo)
+ break;
+ ret = ptrace_getsiginfo(child, psiginfo);
if (!ret)
- ret = copy_siginfo_to_user(datavp, &siginfo);
+ ret = copy_siginfo_to_user(datavp, psiginfo);
+ kvfree(psiginfo);
break;
case PTRACE_SETSIGINFO:
--
2.43.0